Roofer&#39;s knife



April 6, 1954 D. -r. TWISS ROOFER'S KNIFE Filed March 15, 1950 INVENTOR.DONALD T TWISS BY %4%%44 HIS 'A ORNEY a FF? 7 FIIG. 12

FIIG. 13

Patented Apr. 6, 1954 UNI-TED STATES PATENT OFFICE ROOFERS KNIFE DonaldT. Twiss, Los Angeles, Calif. Application March 13, 1950, Serial No.149,227

1 Claim. 1

This invention relates to knives for cutting roofing and particularly toan improved form thereof adapted to supplement the usual hand knivesheretofore used and to increase the efficiency and facility with whichroofing may be cut to fit the position in which it is applied.

A great number of buildings are roofed with prepared roofing consistingof several plies of paper impregnated and cemented together with variousasphalt compounds and generally having an outer surface of gravel orcrushed stone. Such roofing is usually sold in rolls and is cut tolength and, where necessary, to width to suit the point of use.Heretofore, the conventional hooked point roofing knives have beenemployed but the gravel and/or stone coated types rapidly dull suchknives unless the strip to be cut is inverted and the cutting done fromthe uncoated side after which the strip is turned back right side up.Also in some cases, the roofing must be cut in place with the stripoverlying another strip and in such cases care must be exercised not tocut the underlying roofing.

With the foregoing considerations in mind, it is an object of theinvention to provide a roofing knife which may be used to cut gravel orstone coated roofing from the outer face, thereby making unnecessary theheretofore necessary extra work of first inverting the roofing strip andthen turning it back.

Another object of the invention is to provide a roofing knife which isadjustable as to depth of cut to accommodate various thicknesses ofroofing material.

A further object of the invention is to provide a roofing knife in whichthe above desirable objects are achieved and which is designed as anattachment for the conventional roofing knife so that the roofer is notburdened with an extra tool.

Still another object of the invention is to provide a roofing knifehaving a renewable blade of small size so that replacement does notinvolve the purchase of an entire knife and handle as has heretoforebeen required.

With the above objects in view together with such additional objects andadvantages as may subsequently appear, the invention resides in theparts, and in the construction, combination, and arrangement of partsdescribed, by way of example, in the following specifications of certainmodes of execution of the invention, reference being had to theaccompanying drawings forming a part of said specification, and in whichdrawings:

the line 'I1 of Fig. 5,

Fig. 1 is a side elevation of one form of the invention mounted for useon the back of the blade of a conventional roofers knife,

Fig. 2 is an enlarged, top plan view of the form of the invention shownin Fig. 1,

Fig. 3 is an enlarged side elevation of the same side as shown in Fig.1,

Fig. 4 is a rear elevation of the form shown in the preceding figures,

Fig. 5 is an elevation of the side opposite that shown in Figs. 1 and 3,

Fig. 6 is a vertical, medial, sectional view taken on the line 6-4; ofFig. 4,

Fig. 7 is a transverse, sectional view taken on Fig. 8 is a rearelevation of a second mode of execution of the invention,

Fig. 9 is an elevation of the right hand sideof F g- Fig. 10 is a topplan view of Fig. 8,

Fig. 11 is a top plan view of a third mode of execution of theinvention, and

Figs. 12 and 13 are side and rear elevations, respectively, of the thirdform of the invention.

Referring first to the form of the invention shown in Figs. 1 to 7,inclusive, the knife holding means is formed of two reversely formed L-shaped members I and 2 which are united along a portion of their meetingvertical edges by a built-up weld 3. Above the weld the vertical legs ofthe members I and 2 are offset from each other to provide a receivingslot 4 for the back of a conventional roofing knife blade 13. Below theslot 4 the meeting faces of the members I and 2 at their mid-width arerecessed to form a rectangular slot 5 for the shank 6 of a cutting bladeI which projects below the plane of the horizontal legs 8 and 9 of themembers I and 2. The slot 5 may be formed in any suitable manner; ashere shown, a hole I0 is first drilled through the united members andopposite sides of the hole are broached to the size and shape of theblade (see Fig. 7). Alternatively, the meeting faces of the members Iand 2 may be provided with mating shallow grooves before they are weldedtogether. The shank 6 of the knife is clamped in place by a screw IIwhich passes through a hole I2 in the member 2 and is threaded into themember I as best shown in Figs. 2 and 7.

The offset upper portions of the vertical leg portions of the members Iand 2 at their mid width are curved outwardly and thence inwardly toprovide reinforcing ribs I3 and I4 and are inclined slightly toward eachother (see Fig. 4) to accommodate the taper of the roofing knife blade.The member I is provided with a threaded hole IS in which is located aset screw it which clamps the knife blade B against the face of themember 2 and the hole I5 is so disposed that the set screw engages theopposite side of the knife blade at a right angle. The lower faces ofthe horizontal legs 8 and 8 of the members i and 2 are curved (see Figs.1, 3, 5, and 6) so that the knife may be rocked to a considerable degreewithout affecting the depth of cut and so that the knife will ride overthe rough surface of the roofing. The knife 1 and its shank G arepreferably formed of a carbide which is much harder than steel andwhich, therefore, is not affected by the stone or gravel coating of theroofing. Due

to its small size, the replacement of blades is in-' expensive despitethe high cost of the carbide as compared to steel. Also it may beclamped to cut at various depths to suit the thickness of the roofingand as it becomes dulled it can be moved further out of the rectangularslot 5 so that a considerable portion of the knife 'l is available foruse.

Preferably, the device is mounted on the back of the knife blade B justat the beginning of the curve leading to the point of the'knife so thatwhen in u e the handle of the roofers knife is inclined upwardly in thedirection of out (see Fig. l). The fact that the knife blade 3 istapered assists materially in holding the device on the knife bladeduring cutting, and since the blade 1 is disposed directly beneath theblade B, it is easy to follow a line even though the blade 7 is obscuredfrom view.

Referring next to the form of the invention shown in Figs. 8, 9 and 10,the holder If is formed from a steel casting or forging of inverted T-shape as viewed from either end provided with a knife blade receivingslot 18 and an angularly disposed set screw i9 adapted to clamp theholder to a roofers knife blade B in the slot is. Disposed centrally ofthe holder is a rectangular hole 28 formed in the manner first describedin the description of the first form of the invention. Located withcapacity for endwise adjustment in the hole 20 is the rectangular shank21 of a carbide knife 22 of the same type as the knife '5 in the firstform of the invention and a set screw 23 threaded into the front edge ofthe holder engages the shank Zl to clamp it in adjusted position. Thelaterally extending arms 2 and 25 on each side of the knife serve toguide it in the same manner as the members 8 and 9 in the first form ofthe invention. The use and advantages are the same as the firstdescribed form of the invention but the design is better adapted toquantity production.

The form of the invention shown in Figs. 11, 12 and 13 embodies a holder28 formed from a short length of round steel. On one side face a 4 knifeblade receiving slot 21 is provided and offset from this slot andextending through the holder is a rectangular hole 28 in which the shankportion 29 of a carbide blade 30 is disposed. At one side of the slot 21the holder is provided with a set screw 3| adapted to simultaneouslyclamp the holder to the blade of a roofers knife and through theengagement of the blade with the shank 29 of the knife 30, to clamp theknife 38 in adjusted position. The mode of use and the advantageachieved thereby are the same as in the preceding forms of theinvention, the added advantage being that of simplification in theelimination of one of the setscrews, although the resulting device issomewhat heavier than the preceding forms.

I claim:

A device for cutting mineral coated roofing materials incident to thelaying of such materials, said device comprising a knife blade formed ofmaterial of sufficient hardness to readily cut roofing material and themineral coating thereof; said knife blade having a rectangular shank,and a holder therefor in which said shank is mounted; said holdercomprising a body having a slot extending across one end thereof forreception of the back of a blade of a roofers knife and being providedwith setscrew mean extending from the exterior of said body through aside wall of said slot operable to clamp the roofers knife blade againstthe opposite side Wall of said slot, a rectangular opening extendingthrough said body member from the bottom of said slot and emerging atthe end of said body member opposite said slotted end thereof; saidrectangular shank of said knife blade being disposed in said rectangularopening with the cutting edg thereof disposed beyond said opposite endof said body member, and other setscrew means carried by said bodymember extending from the exterior thereof into said rectangular openingoperable to clamp said rectangular shank therein in adjusted positionlongitudinally of said opening; said body member at said opposite endthereof having roofing surface contacting flange portion extendinglaterally in a common plane from both sides of said knife shank andbeing effective to determine the depth of cut made by said knife bladeincl: dent to the adjusted position thereof in said rectangular opening.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 538,459 McCausland Apr. 30, 1895 718,882 Savaria Jan. 20, 19031,129,310 Platt Feb. 23, 1915 1,940,270 Rainwater Dec. 19, 19332,282,729 Knauf May 12, 1942. 2,579,773 Williams Dec. 25, 1951

